The Google Music Web app for iOS, which Google announced on Twitter Thursday, allows you to browse your music by artist, album, song, playlist, and genres in a basic gray interface, somewhat similar to the native Android app. Music can play in the background and playback can be controlled with the standard iOS play/pause/skip controls, but Google offers no option to cache music for offline playback or to create new playlists.

Announced in May, Google’s Music service received lukewarm reviews. For now, it’s only available by invitation (request one here, in the U.S. only) and is so far free to use during the beta period. But Google Music has a significant drawback, as Google didn’t secure deals with record labels for the service.

To access their music from an Android or iOS device, Google Music users must upload their song library (up to 20,000 songs) to Google’s servers, instead of just matching it to a master copy in the cloud, as Apple’s iTunes Match service promises. Depending on the size of your music library and your Internet connection speed, this process can be very lengthy.

A Mixed Bag of Treats

Amazon didn’t secure label deals either for its rival Cloud Player service, so its users must follow a similar process. Google Music, however, is one step ahead of Amazon, as its iOS Web app works on both iPhones and iPads, while Cloud Player’s streaming Web interface works only with iPads. Amazon currently offers a subscription to Cloud Player, with unlimited space for your music (bought via Amazon MP3) and 20GB of cloud storage for $20 per year.

Apple does seem to have the upper hand when it comes to moving your library to the cloud with iTunes Match by simply mirroring your library with the master copies on its servers (tracks not in the store will be uploaded from your computer). Priced at $25 per year, iTunes Match also allows you to download all your songs at a higher bit rate (256kbps), even if your original song were of lower quality. Apple’s yet-to-be-released service does, however, lack streaming options (the feature was briefly available in the iOS 5 beta, but was later disabled via an update) and is missing compatibility with anything else than iTunes (Mac and PC) and iOS devices.

However, the dark horse in the cloud music race among Apple, Google, and Amazon is Spotify with a music streaming service that provides access to some 15 million songs from $5 per month, along with offline access, mobile streaming to iPhone, Android, Windows Phone, and Symbian for just $10 per month.